Search results for "Enterocyte"
showing 10 items of 28 documents
M1 Macrophages Activate Notch Signalling in Epithelial Cells: Relevance in Crohn's Disease
2016
Background: The Notch signalling pathway plays an essential role in mucosal regeneration, which constitutes a key goal of Crohn's disease (CD) treatment. Macrophages coordinate tissue repair and several phenotypes have been reported which differ in the expression of surface proteins, cytokines and hypoxia-inducible factors (HIFs). We analysed the role of HIFs in the expression of Notch ligands in macrophages and the relevance of this pathway in mucosal regeneration. Methods: Human monocytes and U937-derived macrophages were polarized towards the M1 and M2 phenotypes and the expression levels of HIF-1α, HIF-2α, Jagged 1 (Jag1) and delta-like 4 (Dll4) were evaluated. The effects of macrophage…
Tight Junctions as a Key for Pathogens Invasion in Intestinal Epithelial Cells
2021
Tight junctions play a major role in maintaining the integrity and impermeability of the intestinal barrier. As such, they act as an ideal target for pathogens to promote their translocation through the intestinal mucosa and invade their host. Different strategies are used by pathogens, aimed at directly destabilizing the junctional network or modulating the different signaling pathways involved in the modulation of these junctions. After a brief presentation of the organization and modulation of tight junctions, we provide the state of the art of the molecular mechanisms leading to permeability breakdown of the gut barrier as a consequence of tight junctions’ attack by pathogens, including…
Enterocyte Purge and Rapid Recovery Is a Resilience Reaction of the Gut Epithelium to Pore-Forming Toxin Attack.
2016
International audience; Besides digesting nutrients, the gut protects the host against invasion by pathogens. Enterocytes may be subjected to damage by both microbial and host defensive responses, causing their death. Here, we report a rapid epithelial response that alleviates infection stress and protects the enterocytes from the action of microbial virulence factors. Intestinal epithelia exposed to hemolysin, a pore-forming toxin secreted by Serratia marcescens, undergo an evolutionarily conserved process of thinning followed by the recovery of their initial thickness within a few hours. In response to hemolysin attack, Drosophila melanogaster enterocytes extrude most of their apical cyto…
Chronic intestinal inflammation in mice expressing viral Flip in epithelial cells
2018
Viruses are present in the intestinal microflora and are currently discussed as a potential causative mechanism for the development of inflammatory bowel disease. A number of viruses, such as Human Herpesvirus-8, express homologs to cellular FLIPs, which are major contributors for the regulation of epithelial cell death. In this study we analyzed the consequences of constitutive expression of HHV8-viral FLIP in intestinal epithelial cells (IECs) in mice. Surprisingly, expression of vFlip disrupts tissue homeostasis and induces severe intestinal inflammation. Moreover vFlip(IEC-tg) mice showed reduced Paneth cell numbers, associated with excessive necrotic cell death. On a molecular level vF…
Fungal Deoxynivalenol-Induced Enterocyte Distress Is Attenuated by Adulterated Adlay: In Vitro Evidences for Mucoactive Counteraction
2018
Adlay is a cereal crop that has long been used as traditional herbal medicine and as a highly nourishing food. However, deoxynivalenol (DON), the most prevalent trichothecene mycotoxin worldwide, frequently spoils grains, including adlay, via fungal infection. On the basis of an assumption that the actions of DON in the gut could be modified by adlay consumption, we simulated the impacts of co-exposure in enterocytes and investigated the effectiveness of treatment with adlay for reducing the risk of DON-induced inflammation and epithelia barrier injury. In particular, adlay suppressed DON-induced pro-inflammatory signals such as mitogen-activated kinase transduction and the epidermal growth…
Short Term Palmitate Supply Impairs Intestinal Insulin Signaling via Ceramide Production
2016
International audience; The worldwide prevalence of metabolic diseases is increasing, and there are global recommendations to limit consumption of certain nutrients, especially saturated lipids. Insulin resistance, a common trait occurring in obesity and type 2 diabetes, is associated with intestinal lipoprotein overproduction. However, the mechanisms by which the intestine develops insulin resistance in response to lipid overload remain unknown. Here, we show that insulin inhibits triglyceride secretion and intestinal microsomal triglyceride transfer protein expression in vivo in healthy mice force-fed monounsaturated fatty acid-rich olive oil but not in mice force-fed saturated fatty acid…
Autoimmune enteropathy and colitis in an adult patient
2003
The presence of circulating autoantibodies to gut enterocytes has been very rarely described in adults and is considered a possible cause of refractory sprue. Our aims was to describe the case of an adult patient with serum anti-enterocyte autoantibodies associated with a clinical picture characterized by involvement of both the small intestine and colon. A female, age 50, had suffered from diarrhea with mucus and blood, abdominal pain, thinness, anemia, and leukopenia since the age of 20. She also suffered from HCV infection and had mild chronic hepatitis. Family history was positive for autoimmunity. Symptoms were reported to worsen after eating gluten-containing foods, but anti-transglut…
Noroviral P-Particles as an In Vitro Model to Assess the Interactions of Noroviruses with Probiotics
2014
Noroviruses (NoVs) are the main etiologic agents of acute epidemic gastroenteritis and probiotic bacteria have been reported to exert a positive effect on viral diarrhea. The protruding (P) domain from NoVs VP1 capsid protein has the ability to assemble into the so-called P-particles, which retain the binding ability to host receptors. We purified the P-domains from NoVs genotypes GI.1 and GII.4 as 6X(His)-tagged proteins and determined that, similar to native domains, they were structured into P-particles that were functional in the recognition of the specific glycoconjugated receptors, as established by surface plasmon resonance experiments. We showed that several lactic acid bacteria (pr…
Intestinal Scavenger Receptors Are Involved in Vitamin K 1 Absorption
2014
International audience; Vitamin K-1 (phylloquinone) intestinal absorption is thought to be mediated by a carrier protein that still remains to be identified. Apical transport of vitamin K-1 was examined using Caco-2 TC-7 cell monolayers as a model of human intestinal epithelium and in transfected HEK cells. Phylloquinone uptake was then measured ex vivo using mouse intestinal explants. Finally, vitamin K-1 absorption was compared between wild-type mice and mice overexpressing scavenger receptor class B type I (SR-BI) in the intestine and mice deficient in cluster determinant 36 (CD36). Phylloquinone uptake by Caco-2 cells was saturable and was significantly impaired by co-incubation with al…
Luminal Lipid Regulates CD36 Levels and Downstream Signaling to Stimulate Chylomicron Synthesis
2011
International audience; The membrane glycoprotein CD36 binds nanomolar concentrations of long chain fatty acids (LCFA) and is highly expressed on the luminal surface of enterocytes. CD36 deficiency reduces chylomicron production through unknown mechanisms. In this report, we provide novel insights into some of the underlying mechanisms. Our in vivo data demonstrate that CD36 gene deletion in mice does not affect LCFA uptake and subsequent esterification into triglycerides by the intestinal mucosa exposed to the micellar LCFA concentrations prevailing in the intestine. In rodents, the CD36 protein disappears early from the luminal side of intestinal villi during the postprandial period, but …